To a certain extent, this happens in many other ways at schools as well. I mean, those kids with very athletic, or sports oriented, parents, may be more driven or have better guidance in athletic endeavors that would my kids. But we seem not to care about that (until the parents are screaming during a game).
And likewise with music, or art, and so on. So I think I've decided not to get too concerned about how others might view my daughter's work on her project. It would be unfair (to her) if I decided not to give her explanations that were the benefit of my own experience.
That doesn't mean that it's a purely good thing for society. It is the societal perspective that timr most likely had in mind.
A thought experiment: If Bill Gates decided to recruit the top 10,000 maths teachers in the world and shutter them away in a warehouse to perfect the ideal maths lessons solely for his children, would just be "one of the wonderful things about parenting"?
You say that as if it's a bad thing. The thing you seem to be complaining about is one of the wonderful things about parenting. I.e. to impart/share/teach/give what you have accumulated over your life. Whether that is something physical, or intangible such as knowledge, makes no difference.